Frequent problems

Figure layout

Cutoff labels

If the axis ticks are too long, the axis labels might be outside of the figure. When saving the figure, the labels can be cutoff.

For instance the following code produces a cutoff y-axis label.

#include "../../matplotlibcpp.h"
#include <Eigen/Dense>
#include <iostream>

namespace plt = matplotlibcpp;

int main() {
  Eigen::VectorXd x = Eigen::VectorXd::LinSpaced(200, 0, 6);
  Eigen::VectorXd y, z;

  // y = exp(sin(x)), z = exp(cos(z))
  y = x.array().sin().exp().matrix();
  z = x.array().cos().exp().matrix();

  plt::figure();

  plt::loglog(x, y);
  plt::loglog(x, z);

  plt::xlabel("Time in lecture");
  plt::ylabel("Student confusion");

  plt::grid();
  plt::savefig("loglog.pdf"); // !
}

The output is

To fix this problem we can tell MPL to use the available space on the empty sides of the figure, which can be done either by a call to tight_layout or specifiying bbox_inches="tight" in savefig.

Thus the issue is fixed by

plt::savefig("loglog.pdf", {{"bbox_inches", "tight"}}); // !